Currently, there is a focus of attention on light-emitting devices that utilize electroluminescence (called simply “EL” hereinbelow) by the re-coupling of charge-carriers (holes or electrons) in a material, for example, which are emitted upon application of an electric field. For example, EL display devices in which a display panel formed by injection-type organic EL elements that employ organic compound materials is installed have been developed. Organic EL elements include red EL elements that have a structure that emits light of a red color, green EL elements that have a structure that emits light of a green color, and yellow EL elements with a structure that emits light of a yellow color. A color display device can be implemented if these three organic EL elements that emit light in red, blue, and green (RGB) form one pixel light-emitting unit and a plurality of pixels are disposed in a matrix shape on a panel section. As drive systems for a display panel formed by this color display device, a passive matrix drive type and active matrix drive type are known. In comparison with a passive matrix type EL display device, an active matrix drive type EL display device has the benefit of having low power consumption little crosstalk between pixels and is particularly suited to a large screen display device and high definition display device.
A display panel of an active matrix drive type EL display device has anode supply lines, cathode supply lines, and scanning lines that are charged with horizontal scanning and data lines that are arranged intersecting each of the scanning lines formed in the form of a grating. RGB subpixels are formed at the respective RGB intersections of the scanning lines and signal lines. A scanning line is connected to the gate of the Field Effect Transistor (FET) used for the scanning line selection for each subpixel, a signal line is connected to the drain of the FET, and the gate of the FET used for light emission driving is connected to the source of the FET. A drive voltage is applied via an anode supply line to the source of the light-emission drive FET and the anode terminal of the EL element is connected to the drain. A capacitor is connected between the gate and source of the light-emitting drive FET. Furthermore, a ground potential is applied via the anode supply line to the cathode terminal of the EL element.
For example, there is a prior invention (See Patent Literature 1) as shown in FIG. 1 having a structure of an organic light-emitting transistor. This transistor comprises a light-emitting body which is made of an anode ND and a cathode CA of which a part is installed opposed to each other through a luminous material layer LM on a substrate SB; and an auxiliary electrode XE which is formed on the one face of an insulating layer IL opposite to the other face facing the cathode CA and the luminous material layer LM of the anode ND side. In the organic light-emitting transistor structure, a voltage is applied between the auxiliary electrode XE and the cathode CA so that it may be in the same direction as the direction of the voltage that is applied between the anode ND and the cathode CA. In the case of a multicolored organic EL display that uses such organic light-emitting transistors, there are required both of a selectively changing of the material used for the luminous material layer LM and a voltage control that is adapted to the respective luminous material properties in order to change the brightness.    [Patent Literature 1] Japanese Patent Application Laid Open No. 2002-343578